当前位置:科学网首页 > 基金首页 > 辐射诱导马氏体相变的规律及其机理研究

国家自然科学基金项目查询

辐射诱导马氏体相变的规律及其机理研究

批准号10175042 学科分类肿瘤生物治疗 ( H1611 )
项目负责人宋悦 负责人职称 依托单位电子科技大学
资助金额0.00
万元
项目类别青年科学基金项目 研究期限2002 年 01 月 01 日 至
2004 年 12 月 01 日
中文主题词记忆合金;马氏体相变;辐照效应;原位电子显微观察;非晶化转变
英文主题词Shape memory alloys;martensitic transformation;irradiation effect; in situ transmission electron microscopy; amorphization

摘要

中文摘要 辐照致使合金材料的非晶化问题得到了较多的关注和研究,而非常重要的合金马氏体相变的辐照效应及其机理的研究还鲜见报道。钛镍基形状记忆合金及薄膜具有丰富的马氏体相变,在核环境中作为驱动器和传感器也已引起广泛关注,马氏体相变对这些合金的性能起着非常关键的作用。本申请拟主要对辐照诱导记忆合金马氏体相变的机理进行深入的研究。.....
英文摘要 Shape memory alloys (SMAs) have complex martensitic transformation (MT) potential applications for fission and fusion engineering. The systemic study of effects of irradiation on TiNi-based and Cu-based alloys was conducted. The results show: Small dose electron irradiations can raise the reverse transformation temperatures of TiNiCu SMAs due to clustering of irradiation-induced point defects; The temperature Ms of the onset of R-phase-to-martensite transformation decreased with increasing the electron dose due to Relaxation of the elastic stress fields around the Ti3Ni4 precipitates because of the migration and accumulation of irradiation-induced point defects; Heat treatment and irradiation had a prominent effect on the transformation, but with different characteristics in which the M2 (the second R-phase→martensite transformation) transformation temperature decreased and disappeared with increasing electron fluence; The electron irradiation increases MT by about 20 K due to increase of ?-Nb precipitate after electron irradiation; A model is proposed for the calculation of the irradiation induced changes of the martensitic mt of SMAs. Numerical simulations for TiNi SMAs have shown that upon irradiation the austenite finish temperature Af can be raised slightly at the beginning stage. After that, both Af and the martensite start temperature Ms will decrease strongly after extensive irradiations. Both the dose rate and the temperature of irradiations will affect the changes of Ms and Af. The increase of Af at the beginning of irradiations is resulted from the irradiation induced point defect production that increases mainly the non-chemical term in the Gibbs free energy change of the martensitic transformation. The irradiation induced chemical disordering reduces both the chemical and non-chemical terms in the Gibbs free energy change and leads to the strong decreases of Ms and Af. Electron irradiations were carried out using several different TEMs with different accelerating voltages by a cooperation with the University of Michigan. It was found that a phase transformation occurred under electron irradiation above 350 kV, but never appeared at 340 kV or lower accelerating voltage. The mechanism of Electron-irradiation-induced the martensitic transformation is due to displacements of atoms from their lattice sites produced by the accelerated electrons. The critical displacement energy of TiNi SMAs is about 18eV. Ion irradiation-induced amorphization in a TiNiCu SMAs has been investigated by means of the in situ transmission electron microscopy (TEM) using IVEM-Tandem Facility at Argonne National Laboratory.
结题摘要 记忆合金具有丰富的马氏体相变,在核技术领域有广阔的应用前景。对TiNi基和Cu基记忆合金马氏体相变的辐照效应进行了深入系统的研究,发现辐照产生的缺陷对不同成分和热处理状态的样品的马氏体相变的影响有明显的差异,如电子辐照TiNiCu合金产生的点缺陷(团)与马氏体变体作用使相变温度升高;电子辐照TiNi产生的点缺陷(团)与样品中Ti3Ni4沉淀相周围的应变场作用,极大地降低了马氏体相变开始温度;对TiNi多步马氏体相变的影响得到了与热处理相比有不同的物理现象和机理,在较小注量便完全抑制了第二步马氏体相变;而TiNiNb则是通过辐照诱生富Nb沉淀相使马氏体相变温度升高。对大注量(~1dpa,强烈降低相变温度)和小注量辐照出现的不同的物理现象,理论研究表明小注量(~10-5dpa)辐照产生的点缺陷使相变温度升高,而大注量(~1dpa)产生原子无序却使相变温度降低,成功地将我们的结果与前人的结果统一起来了,给出了辐照影响记忆合金相变温度的统一的物理机制。与密西根大学核工系合作用电镜原位辐照诱发了TiNi合金的马氏体相变,得到其离位阈能为~18eV;还首次原位辐照研究了TiNiCu的非晶化过程。

成果

序号 标题 类型 作者
1 Effect of heating/cooling rate on the transformation temperatures in TiNiCu shape memory alloys 期刊 王治国|祖小涛|
2 Incomplete transformation induced multiple-step transformation in TiNi shape memory alloys 期刊 王治国|祖小涛|
3 形状记忆合金的相变性能及其辐照效应研究 奖励 祖小涛|王治国|霍永忠|林理彬|封向东|

关于我们| 网站声明| 服务条款| 联系方式| RSS| 中国科学报社 京ICP备14006957 京公网安备110402500057号
Copyright @ 2007- 中国科学报社 All Rights Reserved
地址:北京市海淀区中关村南一条乙三号   电话:010-62580783